// CodeMirror, copyright (c) by Marijn Haverbeke and others
// Distributed under an MIT license: http://codemirror.net/LICENSE

/**
 * Author: Koh Zi Han, based on implementation by Koh Zi Chun
 */

(function(mod) {
  if (typeof exports == 'object' && typeof module == 'object')
    // CommonJS
    mod(require('../../lib/codemirror'));
  else if (typeof define == 'function' && define.amd)
    // AMD
    define(['../../lib/codemirror'], mod);
  // Plain browser env
  else mod(CodeMirror);
})(function(CodeMirror) {
  'use strict';

  CodeMirror.defineMode('scheme', function() {
    var BUILTIN = 'builtin',
      COMMENT = 'comment',
      STRING = 'string',
      ATOM = 'atom',
      NUMBER = 'number',
      BRACKET = 'bracket';
    var INDENT_WORD_SKIP = 2;

    function makeKeywords(str) {
      var obj = {},
        words = str.split(' ');
      for (var i = 0; i < words.length; ++i) obj[words[i]] = true;
      return obj;
    }

    var keywords = makeKeywords(
      'λ case-lambda call/cc class define-class exit-handler field import inherit init-field interface let*-values let-values let/ec mixin opt-lambda override protect provide public rename require require-for-syntax syntax syntax-case syntax-error unit/sig unless when with-syntax and begin call-with-current-continuation call-with-input-file call-with-output-file case cond define define-syntax delay do dynamic-wind else for-each if lambda let let* let-syntax letrec letrec-syntax map or syntax-rules abs acos angle append apply asin assoc assq assv atan boolean? caar cadr call-with-input-file call-with-output-file call-with-values car cdddar cddddr cdr ceiling char->integer char-alphabetic? char-ci<=? char-ci<? char-ci=? char-ci>=? char-ci>? char-downcase char-lower-case? char-numeric? char-ready? char-upcase char-upper-case? char-whitespace? char<=? char<? char=? char>=? char>? char? close-input-port close-output-port complex? cons cos current-input-port current-output-port denominator display eof-object? eq? equal? eqv? eval even? exact->inexact exact? exp expt #f floor force gcd imag-part inexact->exact inexact? input-port? integer->char integer? interaction-environment lcm length list list->string list->vector list-ref list-tail list? load log magnitude make-polar make-rectangular make-string make-vector max member memq memv min modulo negative? newline not null-environment null? number->string number? numerator odd? open-input-file open-output-file output-port? pair? peek-char port? positive? procedure? quasiquote quote quotient rational? rationalize read read-char real-part real? remainder reverse round scheme-report-environment set! set-car! set-cdr! sin sqrt string string->list string->number string->symbol string-append string-ci<=? string-ci<? string-ci=? string-ci>=? string-ci>? string-copy string-fill! string-length string-ref string-set! string<=? string<? string=? string>=? string>? string? substring symbol->string symbol? #t tan transcript-off transcript-on truncate values vector vector->list vector-fill! vector-length vector-ref vector-set! with-input-from-file with-output-to-file write write-char zero?',
    );
    var indentKeys = makeKeywords('define let letrec let* lambda');

    function stateStack(indent, type, prev) {
      // represents a state stack object
      this.indent = indent;
      this.type = type;
      this.prev = prev;
    }

    function pushStack(state, indent, type) {
      state.indentStack = new stateStack(indent, type, state.indentStack);
    }

    function popStack(state) {
      state.indentStack = state.indentStack.prev;
    }

    var binaryMatcher = new RegExp(
      /^(?:[-+]i|[-+][01]+#*(?:\/[01]+#*)?i|[-+]?[01]+#*(?:\/[01]+#*)?@[-+]?[01]+#*(?:\/[01]+#*)?|[-+]?[01]+#*(?:\/[01]+#*)?[-+](?:[01]+#*(?:\/[01]+#*)?)?i|[-+]?[01]+#*(?:\/[01]+#*)?)(?=[()\s;"]|$)/i,
    );
    var octalMatcher = new RegExp(
      /^(?:[-+]i|[-+][0-7]+#*(?:\/[0-7]+#*)?i|[-+]?[0-7]+#*(?:\/[0-7]+#*)?@[-+]?[0-7]+#*(?:\/[0-7]+#*)?|[-+]?[0-7]+#*(?:\/[0-7]+#*)?[-+](?:[0-7]+#*(?:\/[0-7]+#*)?)?i|[-+]?[0-7]+#*(?:\/[0-7]+#*)?)(?=[()\s;"]|$)/i,
    );
    var hexMatcher = new RegExp(
      /^(?:[-+]i|[-+][\da-f]+#*(?:\/[\da-f]+#*)?i|[-+]?[\da-f]+#*(?:\/[\da-f]+#*)?@[-+]?[\da-f]+#*(?:\/[\da-f]+#*)?|[-+]?[\da-f]+#*(?:\/[\da-f]+#*)?[-+](?:[\da-f]+#*(?:\/[\da-f]+#*)?)?i|[-+]?[\da-f]+#*(?:\/[\da-f]+#*)?)(?=[()\s;"]|$)/i,
    );
    var decimalMatcher = new RegExp(
      /^(?:[-+]i|[-+](?:(?:(?:\d+#+\.?#*|\d+\.\d*#*|\.\d+#*|\d+)(?:[esfdl][-+]?\d+)?)|\d+#*\/\d+#*)i|[-+]?(?:(?:(?:\d+#+\.?#*|\d+\.\d*#*|\.\d+#*|\d+)(?:[esfdl][-+]?\d+)?)|\d+#*\/\d+#*)@[-+]?(?:(?:(?:\d+#+\.?#*|\d+\.\d*#*|\.\d+#*|\d+)(?:[esfdl][-+]?\d+)?)|\d+#*\/\d+#*)|[-+]?(?:(?:(?:\d+#+\.?#*|\d+\.\d*#*|\.\d+#*|\d+)(?:[esfdl][-+]?\d+)?)|\d+#*\/\d+#*)[-+](?:(?:(?:\d+#+\.?#*|\d+\.\d*#*|\.\d+#*|\d+)(?:[esfdl][-+]?\d+)?)|\d+#*\/\d+#*)?i|(?:(?:(?:\d+#+\.?#*|\d+\.\d*#*|\.\d+#*|\d+)(?:[esfdl][-+]?\d+)?)|\d+#*\/\d+#*))(?=[()\s;"]|$)/i,
    );

    function isBinaryNumber(stream) {
      return stream.match(binaryMatcher);
    }

    function isOctalNumber(stream) {
      return stream.match(octalMatcher);
    }

    function isDecimalNumber(stream, backup) {
      if (backup === true) {
        stream.backUp(1);
      }
      return stream.match(decimalMatcher);
    }

    function isHexNumber(stream) {
      return stream.match(hexMatcher);
    }

    return {
      startState: function() {
        return {
          indentStack: null,
          indentation: 0,
          mode: false,
          sExprComment: false,
        };
      },

      token: function(stream, state) {
        if (state.indentStack == null && stream.sol()) {
          // update indentation, but only if indentStack is empty
          state.indentation = stream.indentation();
        }

        // skip spaces
        if (stream.eatSpace()) {
          return null;
        }
        var returnType = null;

        switch (state.mode) {
          case 'string': // multi-line string parsing mode
            var next,
              escaped = false;
            while ((next = stream.next()) != null) {
              if (next == '"' && !escaped) {
                state.mode = false;
                break;
              }
              escaped = !escaped && next == '\\';
            }
            returnType = STRING; // continue on in scheme-string mode
            break;
          case 'comment': // comment parsing mode
            var next,
              maybeEnd = false;
            while ((next = stream.next()) != null) {
              if (next == '#' && maybeEnd) {
                state.mode = false;
                break;
              }
              maybeEnd = next == '|';
            }
            returnType = COMMENT;
            break;
          case 's-expr-comment': // s-expr commenting mode
            state.mode = false;
            if (stream.peek() == '(' || stream.peek() == '[') {
              // actually start scheme s-expr commenting mode
              state.sExprComment = 0;
            } else {
              // if not we just comment the entire of the next token
              stream.eatWhile(/[^/s]/); // eat non spaces
              returnType = COMMENT;
              break;
            }
          default:
            // default parsing mode
            var ch = stream.next();

            if (ch == '"') {
              state.mode = 'string';
              returnType = STRING;
            } else if (ch == "'") {
              returnType = ATOM;
            } else if (ch == '#') {
              if (stream.eat('|')) {
                // Multi-line comment
                state.mode = 'comment'; // toggle to comment mode
                returnType = COMMENT;
              } else if (stream.eat(/[tf]/i)) {
                // #t/#f (atom)
                returnType = ATOM;
              } else if (stream.eat(';')) {
                // S-Expr comment
                state.mode = 's-expr-comment';
                returnType = COMMENT;
              } else {
                var numTest = null,
                  hasExactness = false,
                  hasRadix = true;
                if (stream.eat(/[ei]/i)) {
                  hasExactness = true;
                } else {
                  stream.backUp(1); // must be radix specifier
                }
                if (stream.match(/^#b/i)) {
                  numTest = isBinaryNumber;
                } else if (stream.match(/^#o/i)) {
                  numTest = isOctalNumber;
                } else if (stream.match(/^#x/i)) {
                  numTest = isHexNumber;
                } else if (stream.match(/^#d/i)) {
                  numTest = isDecimalNumber;
                } else if (stream.match(/^[-+0-9.]/, false)) {
                  hasRadix = false;
                  numTest = isDecimalNumber;
                  // re-consume the intial # if all matches failed
                } else if (!hasExactness) {
                  stream.eat('#');
                }
                if (numTest != null) {
                  if (hasRadix && !hasExactness) {
                    // consume optional exactness after radix
                    stream.match(/^#[ei]/i);
                  }
                  if (numTest(stream)) returnType = NUMBER;
                }
              }
            } else if (/^[-+0-9.]/.test(ch) && isDecimalNumber(stream, true)) {
              // match non-prefixed number, must be decimal
              returnType = NUMBER;
            } else if (ch == ';') {
              // comment
              stream.skipToEnd(); // rest of the line is a comment
              returnType = COMMENT;
            } else if (ch == '(' || ch == '[') {
              var keyWord = '';
              var indentTemp = stream.column(),
                letter;
              /**
                        Either
                        (indent-word ..
                        (non-indent-word ..
                        (;something else, bracket, etc.
                        */

              while ((letter = stream.eat(/[^\s\(\[\;\)\]]/)) != null) {
                keyWord += letter;
              }

              if (
                keyWord.length > 0 &&
                indentKeys.propertyIsEnumerable(keyWord)
              ) {
                // indent-word

                pushStack(state, indentTemp + INDENT_WORD_SKIP, ch);
              } else {
                // non-indent word
                // we continue eating the spaces
                stream.eatSpace();
                if (stream.eol() || stream.peek() == ';') {
                  // nothing significant after
                  // we restart indentation 1 space after
                  pushStack(state, indentTemp + 1, ch);
                } else {
                  pushStack(state, indentTemp + stream.current().length, ch); // else we match
                }
              }
              stream.backUp(stream.current().length - 1); // undo all the eating

              if (typeof state.sExprComment == 'number') state.sExprComment++;

              returnType = BRACKET;
            } else if (ch == ')' || ch == ']') {
              returnType = BRACKET;
              if (
                state.indentStack != null &&
                state.indentStack.type == (ch == ')' ? '(' : '[')
              ) {
                popStack(state);

                if (typeof state.sExprComment == 'number') {
                  if (--state.sExprComment == 0) {
                    returnType = COMMENT; // final closing bracket
                    state.sExprComment = false; // turn off s-expr commenting mode
                  }
                }
              }
            } else {
              stream.eatWhile(/[\w_\-!$%&*+\.\/:<=>?@\^~]/);

              if (keywords && keywords.propertyIsEnumerable(stream.current())) {
                returnType = BUILTIN;
              } else returnType = 'variable';
            }
        }
        return typeof state.sExprComment == 'number' ? COMMENT : returnType;
      },

      indent: function(state) {
        if (state.indentStack == null) return state.indentation;
        return state.indentStack.indent;
      },

      closeBrackets: { pairs: '()[]{}""' },
      lineComment: ';;',
    };
  });

  CodeMirror.defineMIME('text/x-scheme', 'scheme');
});
